Chem 1202 Form 1 Answer Key Fall 2024 Dr Gasery Exam 2 Chapters 16 and 17 1 17 2 Acid Base Equilibria and Aqueous Equilibria Common Ion Effect and Buffers Instructions Use an 8 5 x 11 inch green and white scantron On Side Two of the scantron 1 Print your Last Name then First Name and bubble it in 2 Print and bubble in your complete correct LSU ID number 89 number 3 Bubble 1 in the Grade or Education box On Side One of the scantron 1 Print your name 2 Answers to the exam questions must go on side one Bubble the answers on 3 There is exactly one best answer for each question and you should NOT the scantron sheet using a pencil leave a question blank 4 On a numerical question choose the response closest to the correct answer This exam is closed notes and closed book You are not allowed to use your own scratch paper Only a scientific calculator is allowed during the exam NO graphing calculators Mark your answers in your Exam for future reference You can keep your Exam for further study Present your LSU ID and the front of your exam when submitting your scantron Useful Information and Constants The periodic table is located at the back of the exam Kw 1 0 x 10 14 Molarity mol L pH pKa log base acid 1 1 According to the Arrhenius concept what is an acid a An acid has a bitter taste b An acid can donate one or more protons c An acid increases the concentration of H3O ions in solution d An acid is a substance that can accept a pair of electrons from another substance e An acid is a substance that reacts with the solvent to form the cation formed by autoionization of that solvent 2 If an aqueous solution has a pH of 8 75 what is the concentration of H3O ions H3O 10 pH H3O 10 8 75 3 Which of the following is a WEAK acid a 6 23 x 10 8 b 5 26 x 10 12 c 3 15 x 10 15 d 1 50 x 10 7 e 2 00 x 10 9 a H2CO3 b HClO4 c H2SO4 d HNO3 e HBr a 5 25 b 9 78 c 12 5 d 0 62 e 10 8 4 What is the pH of a 0 030 M NaOH solution at 25 C pOH log 0 030 1 52 pH 14 1 52 12 5 5 Which of the following is an example of a conjugate acid base pair from the weak acid base equilibrium reaction below NaHCO3 aq H3PO4 aq NaH2PO4 aq H2CO3 aq a NaHCO3 and H3PO4 b NaH2PO4 and H2CO3 c NaHCO3 and NaH2PO4 d H3PO4 and H2CO3 e NaHCO3 and H2CO3 6 Which of the following statements is TRUE a A strong base produces a very strong conjugate acid b Strong acids have large pKa values c A pOH of 2 indicates a very strong acid d A weak acid can be concentrated e A weak acid is less dangerous than a strong acid 2 7 Of the following substances which one would be considered a STRONG base a CH3 2NH dimethylamine b H2NNH2 hydrazine c Cu OH 2 d NaOH e NH3 8 Which one of the following is the strongest acid 9 An aqueous solution has a pH of 5 75 What is the concentration of OH pOH 14 5 75 8 25 OH 10 8 25 6 00 x 10 9 M 10 A substance that can act as both an acid and base can be classified as which of the Use the data in the statement below to answer Questions 11 12 A buffer is made up of 1 50 M hypochlorous acid HClO and 1 0 M NaClO in a 0 500 L solution The Ka of HClO is 3 0 x 10 8 11 What is the pH of this buffer solution a HBrO b HBrO2 c HClO2 d HClO3 e HClO4 a 9 24 x 10 11 b 4 13 x 10 10 c 2 79 x 10 8 d 6 00 x 10 9 e 1 78 x 10 6 following terms below a Amphiprotic b Conjugated c Miscible d Saturated e Reactive a 11 5 b 7 56 c 8 38 d 10 8 e 7 35 3 12 If a solution of HCl is added to the buffer solution what will happen a The pH of the buffer will increase significantly b The concentration of HClO will increase and the concentration of NaClO will c NaClO will precipitate out of solution as its acid salt d The concentrations of HClO and NaClO will stay the same e The concentration of HClO will decrease and the concentration of NaClO will 13 What is the pH of a 0 200 M NH3 solution mixed with 0 500 M of NH4Cl at 25oC The decrease increase Kb of NH3 is 1 8 x 10 5 a 8 29 b 8 86 c 5 14 d 4 74 e 7 49 14 Designate the Bronsted Lowry acid and the Bronsted Lowry base on the left side of the equation below Then designate the conjugate acid and the conjugate base on the right side Pick the choice which gives the correct term for one of the substances found in the equation below based on your designations HSO3 aq H3O aq H2SO3 aq H2O l a H2O is the Bronsted Lowry base in this reaction b HSO3 c HSO3 d H3O is the Bronsted Lowry acid in this reaction e H2SO3 is the Bronsted Lowry acid in this reaction is the conjugate base in this reaction is the conjugate acid in this reaction water a NH3 aq H3O aq OH aq N3 aq b NH3 aq H3O aq OH aq NH2 aq c NH3 aq H2O l NH4 d NH3 aq H2O l H3O aq NH2 e NH3 aq H3O aq NH4 aq OH aq aq aq H2O l mixed a CsF and HF b HCN and KCN c NH3 and NH4Cl d H2SO4 and NaCl e CH3COOH and NaCH3COO 16 Which one of the following pairs of substances will NOT form a buffer solution when 15 Which of the following is the correct equilibrium expression for the reaction of NH3 with 4 17 BONUS 4 points When NH3 is titrated with HCl the pH at the equivalence point will 18 BONUS 4 points A strong acid solution is formed by mixing 20 0 mL of 0 010 M HCl be because of the presence of a Greater than 7 NH3 b Greater than 7 Cl c Equal to 7 NH4Cl d Less than 7 NH4 e Less than 7 HCl Weak base strong acid titration with 5 00 mL of 0 020 M HBr What is the pH of this solution a 10 7 b 1 92 c 8 80 d 3 53 e 5 27 Find the total H in the solution of these two strong acids Mol H from HCl 0 0002 mol Mol H from HBr 0 0001 …